earticle

영어

This study was carried out to investigate the effects of the parity, milk yield and milking season on the total milk yield and milk compositions in dairy cattle. A total of 3,064 records, collected from dairy farms between January and December in 2015, were analyzed with the SAS/GLM procedure. The milk yield in the first parity was found to be the lowest level (p<0.05). Significant differences in yield of milk were noticed among the animals in different milk yield groups as well as in different seasons (p<0.05). The differences in milk fat percent was also significantly differed among all categories (p<0.05). Milk yield groups and seasons of production also showed significant differences in the milk protein percent (p<0.05). Milk solids significantly increased with parity in dairy cattle (p<0.05) as the parity progressed. The lowest somatic cell count was observed in the first parity and the significant increase of somatic cell count was found in later parities (p<0.05). We found the negative correlations between the milk yield and milk protein % (-0.534), and between milk yield and total milk solids (-0.370). In contrast, the positive correlations were observed between the milk fat and milk protein (0.600), and between milk fat and total milk solids (0.493). The relationship between % of milk protein and total milk solids was strongly positive (0.833). The model with milk yield and milk fat % showed a low coefficient of regression (R2=0.1426). However, the milk fat % and milk protein % (R2=0.3606), and milk protein % and total milk solids (R2=0.6942) showed relatively greater fits with their respective models. In conclusion, these findings suggest that dairy farmers might be required appropriate management of feeding for improvement of milk yield and milk quality including somatic cell affected by seasonal factors and milk performances.